Title | Branching microtubule nucleation in Xenopus egg extracts mediated by augmin and TPX2. |
Publication Type | Journal Article |
Year of Publication | 2013 |
Authors | Petry, S, Groen, AC, Ishihara, K, Mitchison, TJ, Vale, RD |
Journal | Cell |
Volume | 152 |
Issue | 4 |
Pagination | 768-77 |
Date Published | 2013 Feb 14 |
ISSN | 1097-4172 |
Keywords | Animals, Cell Cycle Proteins, Meiosis, Microscopy, Microtubule-Associated Proteins, Microtubules, Nuclear Proteins, Ovum, Phosphoproteins, Xenopus laevis, Xenopus Proteins |
Abstract | <p>The microtubules that comprise mitotic spindles in animal cells are nucleated at centrosomes and by spindle assembly factors that are activated in the vicinity of chromatin. Indirect evidence has suggested that microtubules also might be nucleated from pre-existing microtubules throughout the spindle, but this process has not been observed directly. Here, we demonstrate microtubule nucleation from the sides of existing microtubules in meiotic Xenopus egg extracts. Daughter microtubules grow at a low branch angle and with the same polarity as mother filaments. Branching microtubule nucleation requires γ-tubulin and augmin and is stimulated by factors previously implicated in chromatin-stimulated nucleation, guanosine triphosphate(GTP)-bound Ran and its effector, TPX2. Because of the rapid amplification of microtubule numbers and the preservation of microtubule polarity, microtubule-dependent microtubule nucleation is well suited for spindle assembly and maintenance.</p> |
DOI | 10.1016/j.cell.2012.12.044 |
Alternate Journal | Cell |
PubMed ID | 23415226 |
PubMed Central ID | PMC3680348 |
Grant List | R37 GM038499 / GM / NIGMS NIH HHS / United States R01 GM039565 / GM / NIGMS NIH HHS / United States K99 GM100013 / GM / NIGMS NIH HHS / United States R01 GM038499 / GM / NIGMS NIH HHS / United States R37 GM039565 / GM / NIGMS NIH HHS / United States GM39565 / GM / NIGMS NIH HHS / United States GM38499 / GM / NIGMS NIH HHS / United States / HHMI_ / Howard Hughes Medical Institute / United States |